All-digital frequency following system
US6181209A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 4, 1998 |
| Grant date | Jan 30, 2001 |
| Priority date | — |
| Expiry date | Dec 4, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L2207/50
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An all-digital frequency following system is provided, which is capable of generating an output frequency which can be either an integral or an irrational multiple of an input frequency. The frequency following system is constructed entirely based on digital devices. It includes a frequency counter, a digital comparator, an up/down counter, and a digitally-controlled oscillator. The frequency counter is used to count the output frequency during each period of the input frequency. At the end of each period of the input frequency, the digital comparator will compare the current output of the frequency counter with a preset reference value to thereby generate a corresponding up/down trigger signal. The up/down counter is set at an initial count which is increased or decreased by one in response to the up/down trigger signal from the digital comparator. The digitally-controlled oscillator is capable of generating an output signal serving as the desired output frequency which is proportional to the output of said up/down counter. The reference value set to the digital comparator is equal to the ratio of the desired output frequency to the input frequency. In the case of irrational multi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.